Shaped articles composed of high-temperature ceramics, that is, of high-melting ceramics, are manufactured from oxides, carbides or nitrides e.g. of the elements uranium, plutonium, gadolinium, silicon, titanium, niobium, zirconium or molybdenum. These articles are made by pressing and are finally compressed by sintering at high temperatures, primarily above 1600.degree. C. The sintering process normally is carried out by hot pressing in furnaces. The furnaces may be operated batchwise, but primarily they are continuously operating horizontal pusher-type sintering furnaces. These furnaces are electrically heated. The furnaces may be operated under vacuum or with a protective gas atmosphere, depending on the sintering material. In continuous furnaces, the sintering material itself is carried in socalled sintering boats of e.g. tungsten which are pushed linearly through the furnace.
These horizontal pusher-type sintering furnaces have various disadvantages with respect to their construction and method of operation. They require a large furnace volume, which leads to long heating-up and cooling-down times. In addition, they require a large amount of space. Further, the operation is not truly continuous because of the interruptions caused by loading and unloading of the sintering boats.
Other problems arise because the sintering boats, which contain the sintering material, must also be heated up and cooled off, which increases energy costs. In addition, the necessary numerous sintering boats require a large outlay of capital.